1. Field of the Invention
The present invention relates to a process for a producing fiber aggregate and an apparatus for producing the same, and more particularly, it relates to a process and an apparatus for obtaining an optimum cylindrical fiber aggregate, in which many of fibers are oriented in the tangent direction of the circumference, especially for the fiber reinforced metal application.
2. Description of the Prior Art
Conventionally, a fiber aggregate of short fibers or whiskers has been produced by the following processes:
A centrifugal forming process (Japanese published unexamined patent application No. 65200/1985) has been employed to form the fiber aggregate. According to the process, a fiber suspension is supplied in a porous cylindrical vessel having a lining of a filtration membrane, and the filtrate is dissipated by the centrifugal force to form a fiber aggregate having a hollow.
A suction forming process has been also employed to form the fiber aggregate. According to the process, a fiber suspension supplied in a cylinder is pressurized by a plunger while forcibly draining the filtrate via the filtering substance from the bottom of the cylinder.
However, the fiber aggregate obtained by the above forming processes have many of fibers oriented in two or three-dimensional direction, and the fiber volume ratio is low. Accordingly, it shows a very poor result in the fiber reinforced metal application aiming to improve the strength and control the thermal expansion.